blue filenames jpeg folders

Could someone please shed some light on this seemingly stupid question -
I have alot of jpegs in My Pictures Folder and have noticed some of them the filename is blue, whilst other jpegs the filename is standard Black.
I notice the smallest things and this has me baffled... can anyone tell me the reason I have googled and googled and found nothing
tried the XP help search nothing.
the color does not discriminate some are right-clicked jpegs some are digital camera can anyone put my query to rest?
I am running XP home and all my picture folders are in "filmstrip" view